Which class of fire is a Class B extinguisher suitable for?

A Class B extinguisher is specifically designed to combat fires that involve flammable liquids such as gasoline, oil, grease, and other similar substances. These types of fires are particularly hazardous because flammable liquids can spread quickly and are often difficult to extinguish once they ignite. Class B extinguishers work by smothering the fire and preventing oxygen from sustaining the combustion process, and they typically use agents such as foam, CO2, or dry chemical agents to effectively extinguish these fires.

In contrast, other types of fire classes have different characteristics and types of fuels involved. Fires involving ordinary combustibles (like wood, paper, and cloth) would typically require a Class A extinguisher. Electrical fires need special considerations due to the electrical components, which are better addressed with Class C extinguishers, while metal fires, which can involve combustible metals such as magnesium and sodium, require specific agents and techniques, often indicated by Class D extinguishers. Thus, Class B extinguishers are specifically tailored and rated for flammable liquid fires, making the correct answer clear.